/*
 * Copyright (C) 2012 Facebook, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.facebook.concurrency;

/**
 * @param <K>
 * @param <V>
 */
public interface EvictionListener<K, V> {
  /**
   * notifies a listener that a key/value pair has been evicted. No guarantee is made that the
   * key/value pair is not re-inserted by the time this occurs (ie, an eviction occurred in the
   * past)
   *
   * @param key key that was evicted
   * @param value value evicted. May be null in the case that either null was inserted, or an
   *     exception was thrown producing the value
   */
  void evicted(K key, V value);
}
